Hybrid power converter

ABSTRACT

A power converter for converting an input voltage at an input of the power converter into an output voltage at an output of the power converter may include a switching node, a power inductor coupled between the switching node and the output, a flying capacitor having a first flying capacitor terminal and a second flying capacitor terminal, a pump capacitor having a first pump capacitor terminal and a second pump capacitor terminal, the second pump capacitor terminal coupled to ground, a first switch coupled between the input and the first flying capacitor terminal, a second switch coupled between the first flying capacitor terminal and the switching node, a third switch coupled between the second flying capacitor terminal and the switching node, a fourth switch coupled between the second flying capacitor terminal and a ground voltage, a fifth switch coupled between the second flying capacitor terminal and the first pump capacitor terminal, and a sixth switch coupled between the output and the first pump capacitor terminal.

FIELD OF DISCLOSURE

The present disclosure relates in general to circuits for electronicdevices, including without limitation personal audio devices such aswireless telephones and media players, and more specifically, to ahybrid buck-boost power converter implemented in a 3-level buck-boosttopology that enables the hybrid power converter to operate in aplurality of operating modes. In particular, the hybrid power converterdisclosed herein supports operation in both buck modes of operation andboost modes of operation, rendering it suitable not only for batterycharging in applications that typically employ single-series-cellbatteries (e.g., mobile phones and other small portable devices), butalso for applications that typically employ multiple-series-cellbatteries (e.g., notebook computers).

BACKGROUND

Personal audio devices, including wireless telephones, such asmobile/cellular telephones, cordless telephones, mp3 players, and otherconsumer audio devices, are in widespread use. Such personal audiodevices may include circuitry for driving a pair of headphones or one ormore speakers. Such circuitry often includes a speaker driver includinga power amplifier for driving an audio output signal to headphones orspeakers. Oftentimes, a power converter may be used to provide a supplyvoltage to a power amplifier in order to amplify a signal driven tospeakers, headphones, or other transducers. A switching power converteris a type of electronic circuit that converts a source of power from onedirect current (DC) voltage level to another DC voltage level. Examplesof such switching DC-DC converters include but are not limited to aboost converter, a buck converter, a buck-boost converter, an invertingbuck-boost converter, and other types of switching DC-DC converters.Thus, using a power converter, a DC voltage such as that provided by abattery may be converted to another DC voltage used to power the poweramplifier. A power converter may be used to provide supply voltage railsto one or more components in a device. A power converter may also beused in other applications besides driving audio transducers, such asdriving haptic actuators or other electrical or electronic loads.Further, a power converter may also be used in charging a battery from asource of electrical energy (e.g., an AC-to-DC adapter).

One type of power converter often used in electronic circuits is ahybrid 3-level buck-boost converter. FIG. 1 depicts an example hybrid3-level buck-boost converter 100, as is known in the art. As shown inFIG. 1 , hybrid 3-level buck-boost converter 100 may include an inputconfigured to receive an input voltage V_(IN) and an output configuredto generate an output voltage V_(OUT) Further, hybrid 3-level buck-boostconverter 100 may include a switching node having a voltage L_(x).Hybrid 3-level buck-boost converter 100 may include a power inductor 102coupled between the switching node and the output. Moreover, hybrid3-level buck-boost converter 100 may include a flying capacitor 104having a first capacitor terminal and a second capacitor terminal. Inaddition, hybrid 3-level buck-boost converter 100 may include aplurality of switches 106 a, 106 b, 106 c, 106 d, and 106 e, whereinswitch 106 a is coupled between the input and the first capacitorterminal, switch 106 b is coupled between the first capacitor terminaland the switching node, switch 106 c is coupled between the secondcapacitor terminal and the switching node, switch 106 d is coupledbetween the second capacitor terminal and a ground voltage, and switch106 e is coupled between the second capacitor terminal and the input.

In operation, switches 106 a, 106 b, 106 c, 106 d, and 106 e may becontrolled to regulate output voltage V_(OUT) to a desired targetvoltage. Depending on input voltage V_(IN) and the desired targetvoltage, hybrid 3-level buck-boost converter 100 may be operated ineither a buck mode (V_(OUT)<V_(IN)) or a boost mode (V_(OUT)>V_(IN)). Inthe boost mode, switches 106 a, 106 d, and 106 e may be controlled toregulate output voltage V_(OUT), while switch 106 b may be leftactivated and switch 106 c may be left deactivated. Hybrid 3-levelbuck-boost converter 100 may periodically cycle between a first phase inwhich switches 106 a and 106 d may be activated (and switch 106 edeactivated) and a second phase in which switch 106 e may be activated(and switches 106 a and 106 d deactivated). In essence, boost modeoperation is similar to operation of a charge-pump (e.g., voltagedoubler), as in the phases of boost operation, voltage L_(x) may varybetween V_(IN) and 2V_(IN). Thus, through boost operation, outputvoltage V_(OUT) can be regulated up to 2V_(IN).

However, situations may exist in which it may be desirable to regulateoutput voltage V_(OUT) to a voltage above 2V_(IN), which is not possiblewith the topology shown in FIG. 1 .

SUMMARY

In accordance with the teachings of the present disclosure, one or moredisadvantages and problems associated with existing topologies forhybrid 3-level buck-boost converters may be reduced or eliminated.

In accordance with embodiments of the present disclosure, a powerconverter for converting an input voltage at an input of the powerconverter into an output voltage at an output of the power converter mayinclude a switching node, a power inductor coupled between the switchingnode and the output, a flying capacitor having a first flying capacitorterminal and a second flying capacitor terminal, a pump capacitor havinga first pump capacitor terminal and a second pump capacitor terminal,the second pump capacitor terminal coupled to ground, a first switchcoupled between the input and the first flying capacitor terminal, asecond switch coupled between the first flying capacitor terminal andthe switching node, a third switch coupled between the second flyingcapacitor terminal and the switching node, a fourth switch coupledbetween the second flying capacitor terminal and a ground voltage, afifth switch coupled between the second flying capacitor terminal andthe first pump capacitor terminal, and a sixth switch coupled betweenthe output and the first pump capacitor terminal.

In accordance with these and other embodiments of the presentdisclosure, a method for converting an input voltage at an input of thepower converter into an output voltage at an output of the powerconverter, is provided for a power converter comprising a switchingnode, a power inductor coupled between the switching node and theoutput, a flying capacitor having a first flying capacitor terminal anda second flying capacitor terminal, a pump capacitor having a first pumpcapacitor terminal and a second pump capacitor terminal, the second pumpcapacitor terminal coupled to ground, a first switch coupled between theinput and the first flying capacitor terminal, a second switch coupledbetween the first flying capacitor terminal and the switching node, athird switch coupled between the second flying capacitor terminal andthe switching node, a fourth switch coupled between the second flyingcapacitor terminal and a ground voltage, a fifth switch coupled betweenthe second flying capacitor terminal and the first pump capacitorterminal, and a sixth switch coupled between the output and the firstpump capacitor terminal. The method may include operating the powerconverter in a forward hybrid boost mode having two sequential phasescomprising a first forward hybrid boost phase in which the first switch,the second switch, the fourth switch, and the sixth switch are activatedand the third switch and the fifth switch are deactivated and a secondforward hybrid boost phase in which the second switch and the fifthswitch are activated and the first switch, the third switch, the fourthswitch, and the sixth switch are deactivated.

In accordance with these and other embodiments of the presentdisclosure, an integrated circuit for use in a power converter forconverting an input voltage at an input of the integrated circuit intoan output voltage at an output of the power converter may include aswitching node, a first switch coupled between the input and a firstnode configured to couple to a first flying capacitor terminal of aflying capacitor, a second switch coupled between the first node and theswitching node, a third switch coupled between the switching node and asecond node configured to couple to a second flying capacitor terminalof the flying capacitor, a fourth switch coupled between the second nodeand a third node at a ground voltage, a fifth switch coupled between thesecond node and a fourth node configured to couple to a first pumpcapacitor terminal of a pump capacitor coupled to a ground voltage at asecond pump capacitor terminal, and a sixth switch coupled between theoutput and the fourth node.

In accordance with these and other embodiments of the presentdisclosure, a power converter system may include a power converterbranch comprising a flying capacitor and a switch network configured toconvert an input voltage of the power converter system into an outputvoltage of the power converter system and an auxiliary branch comprisingan auxiliary capacitor coupled to ground voltage and a second switchnetwork, the auxiliary branch configured to operate in a plurality ofmodes comprising a first mode in which the auxiliary capacitor is usedto charge balance the flying capacitor and a second mode in which theauxiliary capacitor is used to boost an output of the power converterbranch.

In accordance with these and other embodiments of the presentdisclosure, a method may include, in a power converter system having apower converter branch comprising a flying capacitor and a switchnetwork configured to convert an input voltage of the power convertersystem into an output voltage of the power converter system and anauxiliary branch comprising an auxiliary capacitor coupled to groundvoltage and a second switch network, operating the auxiliary branch in aplurality of modes comprising a first mode in which the auxiliarycapacitor is used to charge balance the flying capacitor and a secondmode in which the auxiliary capacitor is used to boost an output of thepower converter branch.

Technical advantages of the present disclosure may be readily apparentto one skilled in the art from the figures, description and claimsincluded herein. The objects and advantages of the embodiments will berealized and achieved at least by the elements, features, andcombinations particularly pointed out in the claims.

It is to be understood that both the foregoing general description andthe following detailed description are examples and explanatory and arenot restrictive of the claims set forth in this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present embodiments and advantagesthereof may be acquired by referring to the following description takenin conjunction with the accompanying drawings, in which like referencenumbers indicate like features, and wherein:

FIG. 1 illustrates a circuit diagram of selected components of anexample hybrid 3-level buck-boost converter, as is known in the art;

FIG. 2 illustrates a circuit diagram of selected components of anexample hybrid 3-level buck-boost converter, in accordance withembodiments of the present disclosure;

FIG. 3 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 2 in a forward hybrid boost mode, in accordance withembodiments of the present disclosure;

FIG. 4 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 2 in a bypass mode, in accordance with embodiments ofthe present disclosure;

FIG. 5 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 2 in a forward 2:1 switched capacitor mode, inaccordance with embodiments of the present disclosure;

FIG. 6 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 2 in a forward 2-level buck mode, in accordance withembodiments of the present disclosure;

FIG. 7 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 2 in a forward 3-level buck mode for duty cycles lessthan 0.5, in accordance with embodiments of the present disclosure;

FIG. 8 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 2 in a forward 3-level buck mode for duty cyclesgreater than 0.5, in accordance with embodiments of the presentdisclosure;

FIG. 9 illustrates a circuit diagram of selected components of anotherexample hybrid 3-level buck-boost converter, in accordance withembodiments of the present disclosure;

FIG. 10 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a forward hybrid boost mode, in accordance withembodiments of the present disclosure;

FIG. 11 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a bypass mode, in accordance with embodiments ofthe present disclosure;

FIG. 12 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a forward 2:1 switched capacitor mode, inaccordance with embodiments of the present disclosure;

FIG. 13 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a forward 2-level buck mode, in accordance withembodiments of the present disclosure;

FIG. 14 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a forward 3-level buck mode for duty cycles lessthan 0.5, in accordance with embodiments of the present disclosure;

FIG. 15 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a forward 3-level buck mode for duty cyclesgreater than 0.5, in accordance with embodiments of the presentdisclosure;

FIG. 16 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a forward 3-level buck mode with flying capacitorbalancing for duty cycles less than 0.5, in accordance with embodimentsof the present disclosure; and

FIG. 17 illustrates operation of the hybrid 3-level buck-boost converterdepicted in FIG. 9 in a forward 3-level buck mode with flying capacitorbalancing for duty cycles greater than 0.5, in accordance withembodiments of the present disclosure.

DETAILED DESCRIPTION

FIG. 2 illustrates a circuit diagram of selected components of anexample hybrid 3-level buck-boost converter 200A, in accordance withembodiments of the present disclosure. As shown in FIG. 2 , hybrid3-level buck-boost converter 200A may include an input configured toreceive an input voltage V_(IN) and an output configured to generate anoutput voltage V_(OUT) Further, hybrid 3-level buck-boost converter 200Amay include a switching node having a voltage L_(x). Hybrid 3-levelbuck-boost converter 200A may also include a power inductor 202 coupledbetween the switching node and the output. Moreover, hybrid 3-levelbuck-boost converter 200A may include a flying capacitor 204 having afirst flying capacitor terminal and a second flying capacitor terminaland a pump capacitor 208 having a first pump capacitor terminal and asecond pump capacitor terminal, wherein the second pump capacitorterminal may be coupled to ground. In addition, hybrid 3-levelbuck-boost converter 200A may include a plurality of switches 206 a, 206b, 206 c, 206 d, 206 e, and 206 f, wherein switch 206 a is coupledbetween the input and the first flying capacitor terminal, switch 206 bis coupled between the first flying capacitor terminal and the switchingnode, switch 206 c is coupled between the second flying capacitorterminal and the switching node, switch 206 d is coupled between thesecond flying capacitor terminal and a ground voltage, switch 206 e iscoupled between the second flying capacitor terminal and the first pumpcapacitor terminal, and switch 206 f is coupled between the output andthe first pump capacitor terminal.

In operation, a control circuit (not shown for purposes of clarity andexposition) may control switching of switches 206 a, 206 b, 206 c, 206d, 206 e, and 206 f to regulate output voltage V_(OUT) to a desiredtarget voltage. To that end, the control circuit may cause hybrid3-level buck-boost converter 200A to operate, at any given time, in oneof a plurality of modes, as depicted in FIGS. 3-8 , and described ingreater detail below.

Perhaps most advantageously over the existing topology shown in FIG. 1 ,hybrid 3-level buck-boost converter 200A may be operated in a forwardhybrid boost mode, depicted in FIG. 3 , which enables regulation ofoutput voltage V_(OUT) to a desired target voltage greater than 2V_(IN).As shown in FIG. 3 , operation in the forward hybrid boost mode mayinclude commutation of switches between a first phase (φ1) and a secondphase (φ2). Switch 206 b may remain activated and switch 206 c mayremain deactivated during both the first phase and the second phase, andswitches 206 a, 206 d, 206 e, and 206 f may be commutated to regulateoutput voltage V_(OUT), with switches 206 a and 206 d activated (andswitch 206 e deactivated) during the first phase, and switch 206 eactivated (and switches 206 a, 206 d, and 206 f deactivated) during thesecond phase. During the first phase, a voltage V_(PUMP) across pumpcapacitor 208 may be charged to output voltage V_(OUT), allowing theswitching node voltage L_(x) to switch between V_(IN) andV_(OUT)+V_(IN). Accordingly, output voltage V_(OUT) is not limited to2V_(IN), and may be set to a desired target voltage greater than2V_(IN). Notably, by swapping the input and output of hybrid 3-levelbuck-boost converter 200A, hybrid 3-level buck-boost converter 200A mayoperate the same two phases depicted in FIG. 3 in order to operate in areverse hybrid buck mode.

In addition, hybrid 3-level buck-boost converter 200A may be operated ina bypass mode, depicted in FIG. 4 , which bypasses input voltage V_(IN)to output voltage V_(OUT). Accordingly, through the entirety ofoperation in bypass mode, switches 206 a and 206 b may remain activated,such that input voltage V_(IN) passes to output voltage V_(OUT) viaswitches 206 a and 206 b and power inductor 202. In some embodiments,switches 206 c, 206 e, and 206 f may also be activated in addition to orin lieu of switches 206 a and 206 b, in order to reduce losses that mayoccur due to the resistance of power inductor 202.

Further, hybrid 3-level buck-boost converter 200A may be operated in aforward 2:1 switched capacitor mode, depicted in FIG. 5 , which mayenable regulation of output voltage V_(OUT) to 2V_(IN). As shown in FIG.5 , operation in the forward 2:1 switched capacitor mode may includecommutation of switches between a first phase (φ1) and a second phase(φ2). Switch 206 f may remain activated during both the first phase andthe second phase, and switches 206 a, 206 b, 206 c, 206 d, and 206 e maybe commutated to regulate output voltage V_(OUT), with switches 206 a,206 c, and 206 e activated (and switches 206 b and 206 d deactivated)during the first phase, and switches 206 b and 206 d activated (andswitches 206 a, 206 c, and 206 e deactivated) during the second phase.

Moreover, hybrid 3-level buck-boost converter 200A may be operated in aforward 2-level buck mode, depicted in FIG. 6 . As shown in FIG. 6 ,operation in the forward 2-level buck mode may include commutation ofswitches between a first phase (φ1) and a second phase (φ2). Switches206 e and 206 f may remain deactivated during both the first phase andthe second phase, and switches 206 a, 206 b, 206 c, and 206 d may becommutated to regulate output voltage V_(OUT), with switches 206 a and206 b activated (and one or both of switches 206 c and 206 ddeactivated) during the first phase, and switches 206 c and 206 dactivated (and one or both switches 206 a and 206 b deactivated) duringthe second phase. Notably, by swapping the input and output of hybrid3-level buck-boost converter 200A, hybrid 3-level buck-boost converter200A may operate the same two phases depicted in FIG. 6 in order tooperate in a reverse 2-level boost mode.

Hybrid 3-level buck-boost converter 200A may also be operated in aforward 3-level buck mode, depicted in FIGS. 7 and 8 . As shown in FIG.7 , for duty cycles of less than 0.5, operation in the forward 3-levelbuck mode may include commutation of switches among a first phase (φ1),a second phase (φ2), a third phase (φ3), and a fourth phase (φ4).Switches 206 e and 206 f may remain deactivated during all four phases,and switches 206 a, 206 b, 206 c, and 206 d may be commutated toregulate output voltage V_(OUT), with switches 206 a and 206 c activated(and switches 206 b and 206 d deactivated) during the first phase,switches 206 c and 206 d activated (and switches 206 a and 206 bdeactivated) during the second phase, switches 206 b and 206 d activated(and switches 206 a and 206 c deactivated) during the third phase, andswitches 206 c and 206 d activated (and switches 206 a and 206 bdeactivated) during the fourth phase. Further, as shown in FIG. 8 , forduty cycles of greater than 0.5, operation in the forward 3-level buckmode may include commutation of switches among a first phase (φ1), asecond phase (φ2), a third phase (φ3), and a fourth phase (φ4). Switches206 e and 206 f may remain deactivated during all four phases, andswitches 206 a, 206 b, 206 c, and 206 d may be commutated to regulateoutput voltage V_(OUT), with switches 206 a and 206 c activated (andswitches 206 b and 206 d deactivated) during the first phase, switches206 a and 206 b activated (and switches 206 c and 206 d deactivated)during the second phase, switches 206 b and 206 d activated (andswitches 206 a and 206 c deactivated) during the third phase, andswitches 206 a and 206 b activated (and switches 206 c and 206 ddeactivated) during the fourth phase. Notably, by swapping the input andoutput of hybrid 3-level buck-boost converter 200A, hybrid 3-levelbuck-boost converter 200A may operate the same four phases depicted inFIGS. 7 and 8 in order to operate in a reverse 3-level boost mode.

FIG. 9 illustrates a circuit diagram of selected components of anotherexample hybrid 3-level buck-boost converter 200B, in accordance withembodiments of the present disclosure. Hybrid 3-level buck-boostconverter 200B may be similar in many respects to hybrid 3-levelbuck-boost converter 200A depicted in FIG. 2 , except that in additionto those components depicted in FIG. 2 , hybrid 3-level buck-boostconverter 200B may include a switch 206 g coupled between the firstflying capacitor terminal and the first pump capacitor terminal. Inoperation, a control circuit (not shown for purposes of clarity andexposition) may control switching of switches 206 a, 206 b, 206 c, 206d, 206 e, 206 f, and 206 g to regulate output voltage V_(OUT) to adesired target voltage. To that end, the control circuit may causehybrid 3-level buck-boost converter 200B to operate, at any given time,in one of a plurality of modes, similar to those modes depicted in FIGS.3-8 , and described in greater detail below with reference to FIGS.10-15 .

Similar to that depicted in FIG. 3 , hybrid 3-level buck-boost converter200B may operate in a forward hybrid boost mode, depicted in FIG. 10 ,which enables regulation of output voltage V_(OUT) to a desired targetvoltage greater than 2V_(IN). As shown in FIG. 10 , operation of hybrid3-level buck-boost converter 200B in the forward hybrid boost mode maybe similar to operation of hybrid 3-level buck-boost converter 200A inthe forward hybrid boost mode, except that in the case of hybrid 3-levelbuck-boost converter 200B, switch 206 g may remain deactivated duringboth the first phase and the second phase. Notably, by swapping theinput and output of hybrid 3-level buck-boost converter 200B, hybrid3-level buck-boost converter 200B may operate the same two phasesdepicted in FIG. 10 in order to operate in a reverse hybrid buck mode.

In addition, similar to that depicted in FIG. 4 , hybrid 3-levelbuck-boost converter 200B may be operated in a bypass mode, depicted inFIG. 11 , which bypasses input voltage V_(IN) to output voltage V_(OUT).Accordingly, through the entirety of operation in bypass mode, switches206 a, 206 g, and 206 f may remain activated, such that input voltageV_(IN) passes to output voltage V_(OUT) via switches 206 a, 206 g, and206 f. In some cases, operation of hybrid 3-level buck-boost converter200B in the bypass mode may be preferable to operation of hybrid 3-levelbuck-boost converter 200A in the bypass mode, in that bypassing throughpower inductor 202 as shown in FIG. 3 may lead to losses (e.g., due toDC resistance of power inductor 202) that may not occur when powerinductor 202 is bypassed as shown in FIG. 11 . In some embodiments,switches 206 b, 206 c, and 206 e may also be activated in addition toswitches 206 a, 206 g, and 206 f, in order to further minimize lossesthat may occur due to resistances of switches 206 a, 206 g, and 206 f.

Further, similar to that depicted in FIG. 5 , hybrid 3-level buck-boostconverter 200B may be operated in a forward 2:1 switched capacitor mode,depicted in FIG. 12 , which may enable regulation of output voltageV_(OUT) to 2V_(IN). As shown in FIG. 12 , operation in the forward 2:1switched capacitor mode may include commutation of switches between afirst phase (φ1) and a second phase (φ2). Switch 206 f may remainactivated and switches 206 b and 206 c may remain deactivated duringboth the first phase and the second phase, and switches 206 a, 206 d,206 e, and 206 g may be commutated to regulate output voltage V_(OUT),with switches 206 a and 206 e activated (and switches 206 d and 206 gdeactivated) during the first phase, and switches 206 d and 206 gactivated (and switches 206 a and 206 e deactivated) during the secondphase. In some cases, operation of hybrid 3-level buck-boost converter200B in the forward 2:1 switched capacitor mode may be preferable tooperation of hybrid 3-level buck-boost converter 200A in the forward 2:1switched capacitor mode, as no current flows through power inductor 202in the forward 2:1 switched capacitor mode of hybrid 3-level buck-boostconverter 200B, whereas current flowing through power inductor 202 inthe forward 2:1 switched capacitor mode of hybrid 3-level buck-boostconverter 200A as shown in FIG. 5 may lead to losses (e.g., due to DCresistance of power inductor 202).

Similar to that depicted in FIG. 6 , hybrid 3-level buck-boost converter200B may operate in a forward 2-level buck mode, depicted in FIG. 13 ,which enables regulation of output voltage V_(OUT) to a desired targetvoltage greater than 2V_(IN). As shown in FIG. 13 , operation of hybrid3-level buck-boost converter 200B in the forward 2-level buck mode maybe similar to operation of hybrid 3-level buck-boost converter 200A inthe forward 2-level buck mode, except that in the case of hybrid 3-levelbuck-boost converter 200B, switch 206 g may remain deactivated duringboth the first phase and the second phase. Notably, by swapping theinput and output of hybrid 3-level buck-boost converter 200B, hybrid3-level buck-boost converter 200B may operate the same two phasesdepicted in FIG. 13 in order to operate in a reverse 2-level boost mode.

Similar to that depicted in FIGS. 7 and 8 , hybrid 3-level buck-boostconverter 200B may operate in a forward 3-level buck mode, depicted inFIGS. 14 and 15 . As shown in FIGS. 14 and 15 , operation of hybrid3-level buck-boost converter 200B in the forward 3-level buck mode maybe similar to operation of hybrid 3-level buck-boost converter 200A inthe forward 3-level buck mode, except that in the case of hybrid 3-levelbuck-boost converter 200B, switch 206 g may remain deactivated duringall four phases. Notably, by swapping the input and output of hybrid3-level buck-boost converter 200B, hybrid 3-level buck-boost converter200B may operate the same four phases depicted in FIGS. 14 and 15 inorder to operate in a reverse 3-level boost mode.

FIG. 16 illustrates operation of the hybrid 3-level buck-boost converter200B in a forward 3-level buck mode with flying capacitor balancing forduty cycles less than 0.5, in accordance with embodiments of the presentdisclosure. Similarly, FIG. 17 illustrates operation of the hybrid3-level buck-boost converter 200B in a forward 3-level buck mode withflying capacitor balancing for duty cycles greater than 0.5, inaccordance with embodiments of the present disclosure.

Operation of hybrid 3-level buck-boost converter 200B in the flyingcapacitor balancing forward 3-level buck mode may be similar tooperation of the forward 3-level buck mode depicted in FIG. 14 . Asshown in FIG. 16 , for duty cycles of less than 0.5, operation in theflying capacitor balancing forward 3-level buck mode may includecommutation of switches among a first phase (φ1), a second phase (φ2), athird phase (φ3), and a fourth phase (φ4). Switch 206 f may remaindeactivated during all four phases, and switches 206 a, 206 b, 206 c,206 d, 206 e, and 206 g may be commutated to regulate output voltageV_(OUT), with switches 206 a, 206 c, and 206 e activated (and switches206 b, 206 d and 206 g deactivated) during the first phase, switches 206c and 206 d activated (and switches 206 a, 206 b, 206 e, and 206 gdeactivated) during the second phase, switches 206 b, 206 d, and 206 gactivated (and switches 206 a, 206 c and 206 e deactivated) during thethird phase, and switches 206 c and 206 d activated (and switches 206 a,206 b, 206 e, and 206 g deactivated) during the fourth phase. Further,as shown in FIG. 17 , for duty cycles of greater than 0.5, operation inthe flying capacitor balancing forward 3-level buck mode may includecommutation of switches among a first phase (φ1), a second phase (φ2), athird phase (φ3), and a fourth phase (φ4). Switch 206 f may remaindeactivated during all four phases, and switches 206 a, 206 b, 206 c,206 d, 206 e, and 206 g may be commutated to regulate output voltageV_(OUT), with switches 206 a, 206 c, and 206 e activated (and switches206 b, 206 d, and 206 g deactivated) during the first phase, switches206 a and 206 b activated (and switches 206 c, 206 d, 206 e, and 206 gdeactivated) during the second phase, switches 206 b, 206 d, and 206 gactivated (and switches 206 a, 206 c, and 206 e deactivated) during thethird phase, and switches 206 a and 206 b activated (and switches 206 c,206 d, 206 e, and 206 g deactivated) during the fourth phase. Notably,by swapping the input and output of hybrid 3-level buck-boost converter200A, hybrid 3-level buck-boost converter 200A may operate the same fourphases depicted in FIGS. 16 and 17 in order to operate in a reverse3-level boost mode.

A main difference between operation in the flying capacitor balancingforward 3-level buck mode of FIGS. 16 and 17 and operating in theforward 3-level buck mode of FIGS. 14 and 15 , is that in the flyingcapacitor balancing forward 3-level buck mode, flying capacitor 204 maybe coupled in series with pump capacitor 208 during the first phase(e.g., via switch 206 e) and flying capacitor 204 may be coupled inparallel with pump capacitor 208 during the third phase (e.g., viaswitch 206 g), which in turn may cause a voltage across flying capacitor204 to remain balanced at a voltage V_(IN)/2.

In some embodiments, certain components of either of hybrid 3-levelbuck-boost converter 200A and hybrid 3-level buck-boost converter 200Bmay be formed within a single integrated circuit while other componentsmay reside external to such integrated circuit. For example, in someembodiments, switches 206 a, 206 b, 206 c, 206 d, 206 e, 206 f, and 206g, as well as control circuitry for controlling switches 206 a, 206 b,206 c, 206 d, 206 e, 206 f, and 206 g, may reside on an integratedcircuit, while power inductor 202, flying capacitor 204, and pumpcapacitor 208 are external to such integrated circuit. As anotherexample, flying capacitor 204, pump capacitor 208, and switches 206 a,206 b, 206 c, 206 d, 206 e, 206 f, and 206 g, as well as controlcircuitry for controlling switches 206 a, 206 b, 206 c, 206 d, 206 e,206 f, and 206 g, may reside on an integrated circuit, while powerinductor 202 resides external to such integrated circuit.

As used herein, when two or more elements are referred to as “coupled”to one another, such term indicates that such two or more elements arein electronic communication or mechanical communication, as applicable,whether connected indirectly or directly, with or without interveningelements.

This disclosure encompasses all changes, substitutions, variations,alterations, and modifications to the example embodiments herein that aperson having ordinary skill in the art would comprehend. Similarly,where appropriate, the appended claims encompass all changes,substitutions, variations, alterations, and modifications to the exampleembodiments herein that a person having ordinary skill in the art wouldcomprehend. Moreover, reference in the appended claims to an apparatusor system or a component of an apparatus or system being adapted to,arranged to, capable of, configured to, enabled to, operable to, oroperative to perform a particular function encompasses that apparatus,system, or component, whether or not it or that particular function isactivated, turned on, or unlocked, as long as that apparatus, system, orcomponent is so adapted, arranged, capable, configured, enabled,operable, or operative. Accordingly, modifications, additions, oromissions may be made to the systems, apparatuses, and methods describedherein without departing from the scope of the disclosure. For example,the components of the systems and apparatuses may be integrated orseparated. Moreover, the operations of the systems and apparatusesdisclosed herein may be performed by more, fewer, or other componentsand the methods described may include more, fewer, or other steps.Additionally, steps may be performed in any suitable order. As used inthis document, “each” refers to each member of a set or each member of asubset of a set.

Although exemplary embodiments are illustrated in the figures anddescribed below, the principles of the present disclosure may beimplemented using any number of techniques, whether currently known ornot. The present disclosure should in no way be limited to the exemplaryimplementations and techniques illustrated in the drawings and describedabove.

Unless otherwise specifically noted, articles depicted in the drawingsare not necessarily drawn to scale.

All examples and conditional language recited herein are intended forpedagogical objects to aid the reader in understanding the disclosureand the concepts contributed by the inventor to furthering the art, andare construed as being without limitation to such specifically recitedexamples and conditions. Although embodiments of the present disclosurehave been described in detail, it should be understood that variouschanges, substitutions, and alterations could be made hereto withoutdeparting from the spirit and scope of the disclosure.

Although specific advantages have been enumerated above, variousembodiments may include some, none, or all of the enumerated advantages.Additionally, other technical advantages may become readily apparent toone of ordinary skill in the art after review of the foregoing figuresand description.

To aid the Patent Office and any readers of any patent issued on thisapplication in interpreting the claims appended hereto, applicants wishto note that they do not intend any of the appended claims or claimelements to invoke 35 U.S.C. § 112(f) unless the words “means for” or“step for” are explicitly used in the particular claim.

What is claimed is:
 1. A power converter for converting an input voltageat an input of the power converter into an output voltage at an outputof the power converter, the power converter comprising: a switchingnode; a power inductor coupled between the switching node and theoutput; a flying capacitor having a first flying capacitor terminal anda second flying capacitor terminal; a pump capacitor having a first pumpcapacitor terminal and a second pump capacitor terminal, the second pumpcapacitor terminal coupled to ground; a first switch coupled between theinput and the first flying capacitor terminal; a second switch coupledbetween the first flying capacitor terminal and the switching node; athird switch coupled between the second flying capacitor terminal andthe switching node; a fourth switch coupled between the second flyingcapacitor terminal and a ground voltage; a fifth switch coupled betweenthe second flying capacitor terminal and first pump capacitor terminal;and a sixth switch coupled between the output and the first pumpcapacitor terminal.
 2. The power converter of claim 1, furthercomprising a control circuit configured to operate the power converterin a forward hybrid boost mode having two sequential phases comprising:a first phase in which the first switch, the second switch, the fourthswitch, and the sixth switch are activated and the third switch and thefifth switch are deactivated; and a second phase in which the secondswitch and the fifth switch are activated and the first switch, thethird switch, the fourth switch, and the sixth switch are deactivated.3. The power converter of claim 1, further comprising a control circuitconfigured to operate the power converter in a bypass mode wherein: thefirst switch and the second switch are activated; the fifth switch andthe sixth switch are deactivated; and at least one of the third switchand the fourth switch are deactivated.
 4. The power converter of claim1, further comprising a control circuit configured to operate the powerconverter in a forward 2:1 switched capacitor mode having two sequentialphases comprising: a first phase in which the first switch, the thirdswitch, the fifth switch, and the sixth switch are activated and thesecond switch and the fourth switch are deactivated; and a second phasein which the second switch, the fourth switch, and the sixth switch areactivated and the first switch, the third switch, and the fifth switchare deactivated.
 5. The power converter of claim 1, further comprising acontrol circuit configured to operate the power converter in a forward2-level buck mode having two sequential phases comprising: a first phasein which the first switch and the second switch are activated, the fifthswitch and the sixth switch are deactivated, and at least one of thethird switch and the fourth switch are deactivated; and a second phasein which the third switch and the fourth switch are activated, the fifthswitch and the sixth switch are deactivated, and at least one of thefirst switch and the second switch are deactivated.
 6. The powerconverter of claim 1, further comprising a control circuit configured tooperate the power converter in a forward 3-level buck mode having foursequential phases comprising: for duty cycles less than 0.5: a firstphase in which the first switch and the third switch are activated andthe second switch, the fourth switch, the fifth switch, and the sixthswitch are deactivated; a second phase in which the third switch and thefourth switch are activated and the first switch, the second switch, thefifth switch, and the sixth switch are deactivated; a third phase inwhich the second switch and the fourth switch are activated and thefirst switch, the third switch, the fifth switch, and the sixth switchare deactivated; and a fourth phase in which the third switch and thefourth switch are activated and the first switch, the second switch, thefifth switch, and the sixth switch are deactivated; and for duty cyclesgreater than 0.5: the first phase in which the first switch and thethird switch are activated and the second switch, the fourth switch, thefifth switch, and the sixth switch are deactivated; the second phase inwhich the first switch and the second switch are activated and the thirdswitch, the fourth switch, the fifth switch, and the sixth switch aredeactivated; the third phase in which the second switch and the fourthswitch are activated and the first switch, the third switch, the fifthswitch, and the sixth switch are deactivated; and the fourth phase inwhich the first switch and the second switch are activated and the thirdswitch, the fourth switch, the fifth switch, and the sixth switch aredeactivated.
 7. The power converter of claim 1, further comprising aseventh switch coupled between the first flying capacitor terminal andthe first pump capacitor terminal.
 8. The power converter of claim 7,further comprising a control circuit configured to operate the powerconverter in a forward hybrid boost mode having two sequential phasescomprising: a first phase in which the first switch, the second switch,the fourth switch, and the sixth switch are activated and the thirdswitch, the fifth switch, and the seventh switch are deactivated; and asecond phase in which the second switch and the fifth switch areactivated and the first switch, the third switch, the fourth switch, thesixth switch, and the seventh switch are deactivated.
 9. The powerconverter of claim 7, further comprising a control circuit configured tooperate the power converter in a bypass mode wherein: the first switch,the sixth switch, and the seventh switch are activated; the secondswitch and the fifth switch are deactivated; and at least one of thethird switch and the fourth switch are deactivated.
 7. he powerconverter of claim 7, further comprising a control circuit configured tooperate the power converter in a forward 2:1 switched capacitor modehaving two sequential phases comprising: a first phase in which thefirst switch, the fifth switch, and the sixth switch are activated andthe second switch, the third switch, the fourth switch, and the seventhswitch are deactivated; and a second phase in which the fourth switch,the sixth switch, and the seventh switch are activated and the firstswitch, the second switch, the third switch, and the fifth switch aredeactivated.
 11. The power converter of claim 7, further comprising acontrol circuit configured to operate the power converter in a forward2-level buck mode having two sequential phases comprising: a first phasein which the first switch and the second switch are activated, the fifthswitch, the sixth switch, and the seventh switch are deactivated, and atleast one of the third switch and the fourth switch are deactivated; anda second phase in which the third switch and the fourth switch areactivated, the fifth switch, the sixth switch, and the seventh switchare deactivated, and at least one of the first switch and the secondswitch are deactivated.
 12. The power converter of claim 7, furthercomprising a control circuit configured to operate the power converterin a forward 3-level buck mode having four sequential phases comprising:for duty cycles less than 0.5: a first phase in which the first switchand the third switch are activated and the second switch, the fourthswitch, the fifth switch, the sixth switch, and the seventh switch aredeactivated; a second phase in which the third switch and the fourthswitch are activated and the first switch, the second switch, the fifthswitch, the sixth switch, and the seventh switch are deactivated; athird phase in which the second switch and the fourth switch areactivated and the first switch, the third switch, the fifth switch, thesixth switch, and the seventh switch are deactivated; and a fourth phasein which the third switch and the fourth switch are activated and thefirst switch, the second switch, the fifth switch, the sixth switch, andthe seventh switch are deactivated; and for duty cycles greater than0.5: the first phase in which the first switch and the third switch areactivated and the second switch, the fourth switch, the fifth switch,the sixth switch, and the seventh switch are deactivated; the secondphase in which the first switch and the second switch are activated andthe third switch, the fourth switch, the fifth switch, the sixth switch,and the seventh switch are deactivated; the third phase in which thesecond switch and the fourth switch are activated and the first switch,the third switch, the fifth switch, the sixth switch, and the seventhswitch are deactivated; and the fourth phase in which the first switchand the second switch are activated and the third switch, the fourthswitch, the fifth switch, the sixth switch, and the seventh switch aredeactivated.
 13. The power converter of claim 7, further comprising acontrol circuit configured to operate the power converter in a flyingcapacitor balancing forward 3-level buck mode having four sequentialphases comprising: for duty cycles less than 0.5: a first phase in whichthe first switch, the third switch, and the fifth switch are activatedand the second switch, the fourth switch, the sixth switch, and theseventh switch are deactivated; a second phase in which the third switchand the fourth switch are activated and the first switch, the secondswitch, the fifth switch, the sixth switch, and the seventh switch aredeactivated; a third phase in which the second switch, the fourthswitch, and the seventh switch are activated and the first switch, thethird switch, the fifth switch, and the sixth switch are deactivated;and a fourth phase in which the third switch and the fourth switch areactivated and the first switch, the second switch, the fifth switch, thesixth switch, and the seventh switch are deactivated; and for dutycycles greater than 0.5: the first phase in which the first switch, thethird switch, and the fifth switch are activated and the second switch,the fourth switch, the sixth switch, and the seventh switch aredeactivated; the second phase in which the first switch and the secondswitch are activated and the third switch, the fourth switch, the fifthswitch, the sixth switch, and the seventh switch are deactivated; thethird phase in which the second switch, the fourth switch, and theseventh switch are activated and the first switch, the third switch, thefifth switch, and the sixth switch are deactivated; and the fourth phasein which the first switch and the second switch are activated and thethird switch, the fourth switch, the fifth switch, the sixth switch, andthe seventh switch are deactivated.
 14. A method for converting an inputvoltage at an input of a power converter into an output voltage at anoutput of the power converter, wherein: the power converter comprises: aswitching node; a power inductor coupled between the switching node andthe output; a flying capacitor having a first flying capacitor terminaland a second flying capacitor terminal; a pump capacitor having a firstpump capacitor terminal and a second pump capacitor terminal, the secondpump capacitor terminal coupled to ground; a first switch coupledbetween the input and the first flying capacitor terminal; a secondswitch coupled between the first flying capacitor terminal and theswitching node; a third switch coupled between the second flyingcapacitor terminal and the switching node; a fourth switch coupledbetween the second flying capacitor terminal and a ground voltage; afifth switch coupled between the second flying capacitor terminal andfirst pump capacitor terminal; and a sixth switch coupled between theoutput and the first pump capacitor terminal; and the method comprisesoperating the power converter in a forward hybrid boost mode having twosequential phases comprising: a first forward hybrid boost phase inwhich the first switch, the second switch, the fourth switch, and thesixth switch are activated and the third switch and the fifth switch aredeactivated; and a second forward hybrid boost phase in which the secondswitch and the fifth switch are activated and the first switch, thethird switch, the fourth switch, and the sixth switch are deactivated.15. The method of claim 14, further comprising operating the powerconverter in a bypass mode wherein: the first switch and the secondswitch are activated; the fifth switch and the sixth switch aredeactivated; and at least one of the third switch and the fourth switchare deactivated.
 16. The method of claim 14, further comprisingoperating the power converter in a forward 2:1 switched capacitor modehaving two sequential phases comprising: a first phase in which thefirst switch, the third switch, the fifth switch, and the sixth switchare activated and the second switch and the fourth switch aredeactivated; and a second phase in which the second switch, the fourthswitch, and the sixth switch are activated and the first switch, thethird switch, and the fifth switch are deactivated.
 17. The method ofclaim 14, further comprising operating the power converter in a forward2-level buck mode having two sequential phases comprising: a first phasein which the first switch and the second switch are activated, the fifthswitch and the sixth switch are deactivated, and at least one of thethird switch and the fourth switch are deactivated; and a second phasein which the third switch and the fourth switch are activated, the fifthswitch and the sixth switch are deactivated, and at least one of thefirst switch and the second switch are deactivated.
 18. The method ofclaim 14, further comprising operating the power converter in a forward3-level buck mode having four sequential phases comprising: for dutycycles less than 0.5: a first phase in which the first switch and thethird switch are activated and the second switch, the fourth switch, thefifth switch, and the sixth switch are deactivated; a second phase inwhich the third switch and the fourth switch are activated and the firstswitch, the second switch, the fifth switch, and the sixth switch aredeactivated; a third phase in which the second switch and the fourthswitch are activated and the first switch, the third switch, the fifthswitch, and the sixth switch are deactivated; and a fourth phase inwhich the third switch and the fourth switch are activated and the firstswitch, the second switch, the fifth switch, and the sixth switch aredeactivated; and for duty cycles greater than 0.5: the first phase inwhich the first switch and the third switch are activated and the secondswitch, the fourth switch, the fifth switch, and the sixth switch aredeactivated; the second phase in which the first switch and the secondswitch are activated and the third switch, the fourth switch, the fifthswitch, and the sixth switch are deactivated; the third phase in whichthe second switch and the fourth switch are activated and the firstswitch, the third switch, the fifth switch, and the sixth switch aredeactivated; and the fourth phase in which the first switch and thesecond switch are activated and the third switch, the fourth switch, thefifth switch, and the sixth switch are deactivated.
 19. The method ofclaim 14, wherein the power converter further comprises a seventh switchcoupled between the first flying capacitor terminal and the first pumpcapacitor terminal.
 20. The method of claim 19, further comprisingoperating the power converter in a forward hybrid boost mode having twosequential phases comprising: a first phase in which the first switch,the second switch, the fourth switch, and the sixth switch are activatedand the third switch, the fifth switch, and the seventh switch aredeactivated; and a second phase in which the second switch and the fifthswitch are activated and the first switch, the third switch, the fourthswitch, the sixth switch, and the seventh switch are deactivated. 21.The method of claim 19, further comprising operating the power converterin a bypass mode wherein: the first switch, the sixth switch, and theseventh switch are activated; the second switch and the fifth switch aredeactivated; and at least one of the third switch and the fourth switchare deactivated.
 19. e method of claim 19, further comprising operatingthe power converter in a forward 2:1 switched capacitor mode having twosequential phases comprising: a first phase in which the first switch,the fifth switch, and the sixth switch are activated and the secondswitch, the third switch, the fourth switch, and the seventh switch aredeactivated; and a second phase in which the fourth switch, the sixthswitch, and the seventh switch are activated and the first switch, thesecond switch, the third switch, and the fifth switch are deactivated.23. The method of claim 19, further comprising operating the powerconverter in a forward 2-level buck mode having two sequential phasescomprising: a first phase in which the first switch and the secondswitch are activated, the fifth switch, the sixth switch, and theseventh switch are deactivated, and at least one of the third switch andthe fourth switch are deactivated; and a second phase in which the thirdswitch and the fourth switch are activated, the fifth switch, the sixthswitch, and the seventh switch are deactivated, and at least one of thefirst switch and the second switch are deactivated.
 24. The method ofclaim 19, further comprising operating the power converter in a forward3-level buck mode having four sequential phases comprising: for dutycycles less than 0.5: a first phase in which the first switch and thethird switch are activated and the second switch, the fourth switch, thefifth switch, the sixth switch, and the seventh switch are deactivated;a second phase in which the third switch and the fourth switch areactivated and the first switch, the second switch, the fifth switch, thesixth switch, and the seventh switch are deactivated; a third phase inwhich the second switch and the fourth switch are activated and thefirst switch, the third switch, the fifth switch, the sixth switch, andthe seventh switch are deactivated; and a fourth phase in which thethird switch and the fourth switch are activated and the first switch,the second switch, the fifth switch, the sixth switch, and the seventhswitch are deactivated; and for duty cycles greater than 0.5: the firstphase in which the first switch and the third switch are activated andthe second switch, the fourth switch, the fifth switch, the sixthswitch, and the seventh switch are deactivated; the second phase inwhich the first switch and the second switch are activated and the thirdswitch, the fourth switch, the fifth switch, the sixth switch, and theseventh switch are deactivated; the third phase in which the secondswitch and the fourth switch are activated and the first switch, thethird switch, the fifth switch, the sixth switch, and the seventh switchare deactivated; and the fourth phase in which the first switch and thesecond switch are activated and the third switch, the fourth switch, thefifth switch, the sixth switch, and the seventh switch are deactivated.25. The method of claim 19, further comprising operating the powerconverter in a flying capacitor balancing forward 3-level buck modehaving four sequential phases comprising: for duty cycles less than 0.5:a first phase in which the first switch, the third switch, and the fifthswitch are activated and the second switch, the fourth switch, the sixthswitch, and the seventh switch are deactivated; a second phase in whichthe third switch and the fourth switch are activated and the firstswitch, the second switch, the fifth switch, the sixth switch, and theseventh switch are deactivated; a third phase in which the secondswitch, the fourth switch, and the seventh switch are activated and thefirst switch, the third switch, the fifth switch, and the sixth switchare deactivated; and a fourth phase in which the third switch and thefourth switch are activated and the first switch, the second switch, thefifth switch, the sixth switch, and the seventh switch are deactivated;and for duty cycles greater than 0.5: the first phase in which the firstswitch, the third switch, and the fifth switch are activated and thesecond switch, the fourth switch, the sixth switch, and the seventhswitch are deactivated; the second phase in which the first switch andthe second switch are activated and the third switch, the fourth switch,the fifth switch, the sixth switch, and the seventh switch aredeactivated; the third phase in which the second switch, the fourthswitch, and the seventh switch are activated and the first switch, thethird switch, the fifth switch, and the sixth switch are deactivated;and the fourth phase in which the first switch and the second switch areactivated and the third switch, the fourth switch, the fifth switch, thesixth switch, and the seventh switch are deactivated.
 26. An integratedcircuit for use in a power converter for converting an input voltage atan input of the integrated circuit into an output voltage at an outputof the power converter, the integrated circuit comprising: a switchingnode; a first switch coupled between the input and a first nodeconfigured to couple to a first flying capacitor terminal of a flyingcapacitor; a second switch coupled between the first node and theswitching node; a third switch coupled between the switching node and asecond node configured to couple to a second flying capacitor terminalof the flying capacitor; a fourth switch coupled between the second nodeand a third node at a ground voltage; a fifth switch coupled between thesecond node and a fourth node configured to couple to a first pumpcapacitor terminal of a pump capacitor coupled to a ground voltage at asecond pump capacitor terminal; and a sixth switch coupled between theoutput and the fourth node.
 27. The integrated circuit of claim 26,further comprising a control circuit configured to operate the powerconverter in a forward hybrid boost mode having two sequential phasescomprising: a first phase in which the first switch, the second switch,the fourth switch, and the sixth switch are activated and the thirdswitch and the fifth switch are deactivated; and a second phase in whichthe second switch and the fifth switch are activated and the firstswitch, the third switch, the fourth switch, and the sixth switch aredeactivated.
 28. The integrated circuit of claim 26, further comprisinga control circuit configured to operate the power converter in a bypassmode wherein: the first switch and the second switch are activated; thefifth switch and the sixth switch are deactivated; and at least one ofthe third switch and the fourth switch are deactivated.
 29. Theintegrated circuit of claim 26, further comprising a control circuitconfigured to operate the power converter in a forward 2:1 switchedcapacitor mode having two sequential phases comprising: a first phase inwhich the first switch, the third switch, the fifth switch, and thesixth switch are activated and the second switch and the fourth switchare deactivated; and a second phase in which the second switch, thefourth switch, and the sixth switch are activated and the first switch,the third switch, and the fifth switch are deactivated.
 30. Theintegrated circuit of claim 26, further comprising a control circuitconfigured to operate the power converter in a forward 2-level buck modehaving two sequential phases comprising: a first phase in which thefirst switch and the second switch are activated, the fifth switch andthe sixth switch are deactivated, and at least one of the third switchand the fourth switch are deactivated; and a second phase in which thethird switch and the fourth switch are activated, the fifth switch andthe sixth switch are deactivated, and at least one of the first switchand the second switch are deactivated.
 31. The integrated circuit ofclaim 26, further comprising a control circuit configured to operate thepower converter in a forward 3-level buck mode having four sequentialphases comprising: for duty cycles less than 0.5: a first phase in whichthe first switch and the third switch are activated and the secondswitch, the fourth switch, the fifth switch, and the sixth switch aredeactivated; a second phase in which the third switch and the fourthswitch are activated and the first switch, the second switch, the fifthswitch, and the sixth switch are deactivated; a third phase in which thesecond switch and the fourth switch are activated and the first switch,the third switch, the fifth switch, and the sixth switch aredeactivated; and a fourth phase in which the third switch and the fourthswitch are activated and the first switch, the second switch, the fifthswitch, and the sixth switch are deactivated; and for duty cyclesgreater than 0.5: the first phase in which the first switch and thethird switch are activated and the second switch, the fourth switch, thefifth switch, and the sixth switch are deactivated; the second phase inwhich the first switch and the second switch are activated and the thirdswitch, the fourth switch, the fifth switch, and the sixth switch aredeactivated; the third phase in which the second switch and the fourthswitch are activated and the first switch, the third switch, the fifthswitch, and the sixth switch are deactivated; and the fourth phase inwhich the first switch and the second switch are activated and the thirdswitch, the fourth switch, the fifth switch, and the sixth switch aredeactivated.
 32. The integrated circuit of claim 26, further comprisinga seventh switch coupled between the first node and the fourth node. 33.The integrated circuit of claim 32, further comprising a control circuitconfigured to operate the power converter in a forward hybrid boost modehaving two sequential phases comprising: a first phase in which thefirst switch, the second switch, the fourth switch, and the sixth switchare activated and the third switch, the fifth switch, and the seventhswitch are deactivated; and a second phase in which the second switchand the fifth switch are activated and the first switch, the thirdswitch, the fourth switch, the sixth switch, and the seventh switch aredeactivated.
 34. The integrated circuit of claim 32, further comprisinga control circuit configured to operate the power converter in a bypassmode wherein: the first switch, the sixth switch, and the seventh switchare activated; the second switch and the fifth switch are deactivated;and at least one of the third switch and the fourth switch aredeactivated.
 35. The integrated circuit of claim 32, further comprisinga control circuit configured to operate the power converter in a forward2:1 switched capacitor mode having two sequential phases comprising: afirst phase in which the first switch, the fifth switch, and the sixthswitch are activated and the second switch, the third switch, the fourthswitch, and the seventh switch are deactivated; and a second phase inwhich the fourth switch, the sixth switch, and the seventh switch areactivated and the first switch, the second switch, the third switch, andthe fifth switch are deactivated.
 36. The integrated circuit of claim32, further comprising a control circuit configured to operate the powerconverter in a forward 2-level buck mode having two sequential phasescomprising: a first phase in which the first switch and the secondswitch are activated, the fifth switch, the sixth switch, and theseventh switch are deactivated, and at least one of the third switch andthe fourth switch are deactivated; and a second phase in which the thirdswitch and the fourth switch are activated, the fifth switch, the sixthswitch, and the seventh switch are deactivated, and at least one of thefirst switch and the second switch are deactivated.
 37. The integratedcircuit of claim 32, further comprising a control circuit configured tooperate the power converter in a forward 3-level buck mode having foursequential phases comprising: for duty cycles less than 0.5: a firstphase in which the first switch and the third switch are activated andthe second switch, the fourth switch, the fifth switch, the sixthswitch, and the seventh switch are deactivated; a second phase in whichthe third switch and the fourth switch are activated and the firstswitch, the second switch, the fifth switch, the sixth switch, and theseventh switch are deactivated; a third phase in which the second switchand the fourth switch are activated and the first switch, the thirdswitch, the fifth switch, the sixth switch, and the seventh switch aredeactivated; and a fourth phase in which the third switch and the fourthswitch are activated and the first switch, the second switch, the fifthswitch, the sixth switch, and the seventh switch are deactivated; andfor duty cycles greater than 0.5: the first phase in which the firstswitch and the third switch are activated and the second switch, thefourth switch, the fifth switch, the sixth switch, and the seventhswitch are deactivated; the second phase in which the first switch andthe second switch are activated and the third switch, the fourth switch,the fifth switch, the sixth switch, and the seventh switch aredeactivated; the third phase in which the second switch and the fourthswitch are activated and the first switch, the third switch, the fifthswitch, the sixth switch, and the seventh switch are deactivated; andthe fourth phase in which the first switch and the second switch areactivated and the third switch, the fourth switch, the fifth switch, thesixth switch, and the seventh switch are deactivated.
 38. The integratedcircuit of claim 32, further comprising a control circuit configured tooperate the power converter in a flying capacitor balancing forward3-level buck mode having four sequential phases comprising: for dutycycles less than 0.5: a first phase in which the first switch, the thirdswitch, and the fifth switch are activated and the second switch, thefourth switch, the sixth switch, and the seventh switch are deactivated;a second phase in which the third switch and the fourth switch areactivated and the first switch, the second switch, the fifth switch, thesixth switch, and the seventh switch are deactivated; a third phase inwhich the second switch, the fourth switch, and the seventh switch areactivated and the first switch, the third switch, the fifth switch, andthe sixth switch are deactivated; and a fourth phase in which the thirdswitch and the fourth switch are activated and the first switch, thesecond switch, the fifth switch, the sixth switch, and the seventhswitch are deactivated; and for duty cycles greater than 0.5: the firstphase in which the first switch, the third switch, and the fifth switchare activated and the second switch, the fourth switch, the sixthswitch, and the seventh switch are deactivated; the second phase inwhich the first switch and the second switch are activated and the thirdswitch, the fourth switch, the fifth switch, the sixth switch, and theseventh switch are deactivated; the third phase in which the secondswitch, the fourth switch, and the seventh switch are activated and thefirst switch, the third switch, the fifth switch, and the sixth switchare deactivated; and the fourth phase in which the first switch and thesecond switch are activated and the third switch, the fourth switch, thefifth switch, the sixth switch, and the seventh switch are deactivated.39. A power converter system comprising: a power converter branchcomprising a flying capacitor and a switch network configured to convertan input voltage of the power converter system into an output voltage ofthe power converter system; and an auxiliary branch comprising anauxiliary capacitor coupled to ground voltage and a second switchnetwork, the auxiliary branch configured to operate in a plurality ofmodes comprising: a first mode in which the auxiliary capacitor is usedto charge balance the flying capacitor; and a second mode in which theauxiliary capacitor is used to boost an output of the power converterbranch.
 40. A method comprising, in a power converter system having apower converter branch comprising a flying capacitor and a switchnetwork configured to convert an input voltage of the power convertersystem into an output voltage of the power converter system and anauxiliary branch comprising an auxiliary capacitor coupled to groundvoltage and a second switch network: operating the auxiliary branch in aplurality of modes comprising: a first mode in which the auxiliarycapacitor is used to charge balance the flying capacitor; and a secondmode in which the auxiliary capacitor is used to boost an output of thepower converter branch.